Scientist urges Reclamation to reduce salmon pre-spawning mortality on American River

by Dan Bacher
Tuesday Apr 9th, 2019 7:14 PM

To ensure that there is less pre-spawning mortality and salmon can spawn in favorable water conditions, Felix Smith urges Reclamation to make an effort to get 59 to 60 DF by mid October and to remain at or below such temperature. He also says the stream flow should be in the range of 1900 to 2400 cfs.

Felix Smith, a Save the American River Association (SARA) board member and the former U.S. Fish and Wildlife biologist who exposed the Kesterson Wildlife Refuge selenium contamination scandal in 1982-83, has just sent a letter to the Bureau of Reclamation regarding his concerns about the operations of Folsom Dam and Reservoir for this summer and fall months.

“My concern is the amount of pre-spawning mortality of the Chinook salmon run that has occurred over the years of 2001 through 2017,” says Smith. “In my opinion, a pre-spawning mortality of more than 5 to 7 percent is uncalled for. An extra effort must be made to reduce such mortality.“

Smith says the Bureau should “prioritize the protection and propagation of Chinook salmon and steelhead. Lets try to reduce the pre-spawning mortality of the Chinook salmon run.”

He says a review of Chinook salmon spawning escapement data for the American River since 2001 shows pre-spawning mortality of 10 percent (2008) to 67 percent in (2001). The lowest per-spawning mortality occurred in 2009 at 4 percent and 6 percent in 2011, “years of very modest runs.”

To ensure that there is less pre-spawning mortality and salmon can spawn in favorable water conditions, Smith urges Reclamation to make an effort to get 59 to 60 DF by mid October and to remain at or below such temperature. He also says the stream flow should be in the range of 1900 to 2400 cfs.

As soon as Smith gets a response to his letter, I will post it here. It would be tragic to see the potential for a robust salmon spawning season on the American this year, due to the heavy Sierra Nevada snowpack, to be diminished due to high spawning mortalities.

We don’t want to see again the 67% mortality that occurred in 2001, a record year for returning American River Chinook salmon, due to low, warm water releases by Reclamation from Nimbus Dam.

The American River is a big contributor to ocean recreational and commercial salmon fisheries. Nimbus Hatchery fall Chinook salmon last year contributed 16 percent of the fish caught in the recreational ocean fishery and 16 percent of the fish landed in the commercial ocean salmon fishery, according to CDFW data.

In 2018, California Department of Fish and Wildlife (CDFW) scientists estimated that a total of 27,302 salmon, including 17,352 adults and 9,951 jacks and jills (two-year-olds), returned to the American River to spawn. This was 36 percent of the total escapement on the Sacramento River watershed. A total of 21,091, or 39 percent, were natural spawners, while 6,212, or 28 percent, were taken into the hatchery.

Here is Smith’s April 3 letter to Ernest A. Conant, Regional Director of the Mid Pacific Region - Bureau of Reclamation and a former lawyer for agribusiness billionaires Stewart and Lynda Resnick, the Kern Water Bank and the Westlands Water District:

Dear Mr. Conant:

This year has been a very good water year. As of March 1, the forecast of runoff for the American River Basin is 3,710,000 acre feet. The month of April with additional snow and rain, the runoff for the American River Basin should be greater.

Irrigated agriculture will benefit. Ground water recharge will benefit. Dry land farming should benefit. The water quality of the Delta should improve as high water cleansed the Delta, especially the south Delta. Hydro power will benefit. All reservoirs are nearly full or full to benefit their beneficiaries.

How does the Bureau of Reclamation plan to operate Folsom Reservoir this summer and fall months to improve conditions to benefit Chinook salmon and steelhead of the American River?

As a suggestion, the Bureau should prioritize the protection and propagation of Chinook salmon and steelhead. Lets try to reduce the pre-spawning mortality of the Chinook salmon run. A review of Chinook salmon spawning escapement data for the American River since 2001 shows pre-spawning mortality of 10 percent (2008) to 67 percent in (2001). The lowest per-spawning mortality occurred in 2009 at 4 percent and 6 percent in 2011, years of very modest runs.

The Bureau seems to wave off mortalities of 12 to 20 percent as normal. Pre-spawning mortality in the range of more than 5 percent is uncalled for and unacceptable. The heaviest mortality occurs during the early portion of the spawning season and gradually decreases.

Therefore let’s make an effort to get 59 to 60 DF by mid October and to remain at or below such temperature. Stream flow should be in the range of 1900 to 2400 cfs. This should reduce the holdover time for adults and encourage spawning to reduce mortality. The earlier the adults spawn the sooner young can move out on winter freshets.

I and the Save the American River Association, the fishing and environmental communities has been waiting for such improvement since the 1992 passage of the Central Valley Project Improvement Act.